did not pass the 100 million mark (excluding the Asian regions) until the 1890's. The United States had only 50 million people in the 1880's and did not pass the 100 million mark until around 1917. And Japan at the time of the restoration (1868) had only 33 million people, slightly less than contemporary Thailand, and did not join the United States and the Soviet Union as the third developed country with over 100 million people until the late 1960's. One consequence of population size, as distinct from either population density or population growth rates, is that it creates special problems in the relationship between central and subordinate units of government. Since it is virtually impossible for a single governmental unit to govern directly a large territory with large numbers of people, some powers are invariably delegated to subordinate governmental units. In large systems, subordinate governmental units have a tendency to seek their own resources, often at the expense of the central government. If central authority is itself weak and divided and its control over resources limited, subordinate authorities may seek greater autonomy. Large underdeveloped states with a weak center are thus particularly vulnerable to conflict between governmental units. When the subordinate governmental units govern distinct cultural regions, as in Pakistan and India (and in Nigeria—the largest African country though it is only half the size of Brazil), then an additional dimension is added to the tensions between central and subordinate authority. Resources-Small vs. Large States. Governments of large states have greater resources available to them than do the governments of smaller states of comparable per capita income. Though all five of the most populous countries in the developing world rank among the lowest in the world in per capita income, four of these five—India, China, Brazil, and Pakistan—rank among the twenty top nations in national income (21, p. 209). By virtue of their size, these countries have large national budgets. Moreover, each of these countries has a large number of scientists and engineers, which makes it possible to make the technological investments that smaller, less developed states cannot make. Large countries, however poor, can amass sizable budgets from small individual contributions with the result that some advanced technologies-nuclear weapons, missiles, and nuclear power stations—are within the technological and resource capacity of several of these nations if they choose to use their resources in these ways. Small developed countries have similar options, but small underdeveloped countries do not. Similarly, large countries have the advantages of potentially large internal markets and the technological and financial resources to choose among a large number of possible investments. Smaller countries may seek the benefits of size by establishing common markets or through forms of economic integration. East African states, for example, have sought to cooperate in the estab-lls and motivation are primary, and local resources and population density arc relatively less important.